1. Field of the Invention
The present invention relates to a magnetic head and, more specifically, to a magnetic head having a bonding structure between a slider and a flexure of a head gimbal assembly for supporting the slider.
2. Description of the Related Art
An HGA (head gimbal assembly) which is widely used in HDD is formed by fixedly bonding a slider having a thin-film magnetic head element (MR element, GMR element) on one end portion of a flexure formed of metallic material which is fixed to a distal end of a load beam. In the related art, a spacer projection is fixed to a surface of the flexure, and the slider is bonded in an area surrounded by the spacer projection where adhesive agent is applied (Japanese Unexamined Patent Application Publication No. 9-282824 (U.S. Pat. No. 5,880,908), Japanese Unexamined Patent Application Publication No. 10-27447, and Japanese Unexamined Patent Application Publication No. 11-39627).
FIG. 9 is a plan view of a distal end portion of the flexure in the related art, and FIG. 10 is a side view showing a state in which the slider is bonded to the flexure. On a flexure 121, there are provided a plurality of spacer projections 122a, 122b, 122c that support a slider 111 of a magnetic head, and electrodes 133a to 133d formed on an FPC substrate which is connected to electrodes 114d (although there are a plurality of electrodes, only one of those is shown in FIG. 10) provided on an end surface B of the slider 111 on a trailing side by ball bonding. A back surface of the slider 111 on the opposite side from a recording-medium-opposed surface (ABS surface) 112, which is a surface opposing to a magnetic recording medium, is bonded to surfaces of the spacer projections 122a to 122c by an adhesive agent 124 applied thereon. After this bonding operation, the electrodes 114d provided on the end surface B of the slider 111 on the trailing side is joined to the electrodes 133a to 133d formed on the flexure 121 via a ball bonding portion 125 formed by ball bonding using gold or the like.
However, in the related art, a length of the bonding portion between the ball bonding portion 125 of the end surface B of the slider 111 on the trailing side and the spacer projection 122b in the vicinity of an end surface A on a leading side is long. Therefore, the ball bonding portion 125 which is a rigid joint becomes a point of support a′ of deformation, and the bonded portion with respect to the adhesive agent becomes a load center b′, so that flatness of the ABS of the slider 111 is susceptible to deformation disadvantageously due to expansion of the flexure 121 by heat applied during bonding and contraction of the flexure 121 by a subsequent cooling operation. There is also a problem such that the flatness of the recording-medium-opposed surface of the slider is significantly changed due to expansion or contraction of the flexure due to change in temperature of operating environment in a state of being assembled in a hard disk device. In this manner, when the flatness of the recording-medium-opposed surface is changed, the raising amount is increased and hence writing/reading performance is lowered. Therefore, it is desirable that the variation of the flatness of the recording-medium-opposed surface of the slider is small.